Engine starter gearing



F. T. CHRISTIAN ENGINE STARTER GEARING Aug. 24, 1943.

Filed Nov. 27, 1941 INV ENT OR.

jll llllm i fllllllllll Patented Aug. 24, 1943 ENGINE STARTER GEARING Frank T. Christian, Elmira, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 27, 1941, Serial No. 420,662

4 Claims.

The present invention relates to engine starter gearing of the type which includes a threaded connection for traversing and actuating a starter pinion, and more particularly to a device for ensuring engagement of the starter pinion with an engine gear upon actuation of the starting motor.

In some starter drive installations, particularly of the so-called double gear reduction type in which the pinion is driven from th starting motor through the reduction gearing, diiiiculty has been encountered in ensuring the automatic traversal of the pinion, especially in the pres ence of dirty and/or congealed lubricant, mud or ice on the component parts of the drive. In order to overcome this difficulty, various forms of detent have been proposed for preventing rotation of the pinion so as to ensure its traversal, one such being illustrated in the application of Elkin, Serial Number 392,724, filed May 9, 1941.

That application discloses a detent which is moved into engagement with a threaded starter pinion by an electro-magnet energized concurrently with the starting motor, and which detent is moved out of operative position after a short time delay provided by the operation of a releasing relay. This form of jab detent is well adapted for installations in which only a small amount of rotation of the starting motor is required to move the pinion into initial engagement with the engine gear. drive, however, such as the double gear reduction types, it is desirable to be able to extend and control the time interval during which the detent remains efiective in order to ensure proper engagement of the pinion while avoiding the possibility of milling off the detent by holding it down against the pinion after cranking of the engine has commenced.

It is an object of the present invention to pro- In other forms of vide a novel engine starter incorporating a pln-' ion having a threaded connection with a starting motor and a latch or detent for resisting rotation of th pinion in order to ensure the traversal thereof when the starting motor is actuated.

It is another object to provide such a device having a time delay for controlling the release of the detent.

It is a further object to provide such a device in which the'detent is actuated by an electromagnet which is energized concurrently with the starting motor.

It is another object to provide such a device in which the electro-magnet is deenergized by a relay, and incorporating means for delaying efiective energization of the relay for a predetermined time.

Further objects and advantages will be apparent from the following description taken in connection withv the accompanying drawing, in which:

Fig. 1 is a semi-diagrammatic illustration of a starting system incorporating a preferred embodiment of the invention; and

Fig. 2 is a similar view of an alternative form of the invention.

In Fig. 1 of the drawing there is illustrated a starting circuit including a battery I grounded at 2 and connected by a starting switch 3 and cable 4 to a starting motor 5. The starting motor illustrated is a heavy duty type having an extended armature shaft 6 which is connected through reduction gear l and 8 to a screw shaft 9 on which a pinion II is threadedfor longitudinal movement into and out of engagement with a gear I2 of an engine to be started.

Means for resisting initial rotation of the pinion I I in order to ensure its longitudinal movement into engagement with th engine gear is provided in the'form of a, detent I3 which is movable by means ofan electro-magnet I4 into position where the end of the detent enters between the teeth of the pinion so as to resist its rotation. Means for actuating the detent I3 is provided in the. form of a connection to the starting cable Ii including a lead IS, a relay i=8 having normally closed contacts ll, I8 and a lead I9 connected to the electro-magnet I4 which is grounded at 2|, to complete the actuating circuit.

According to the present invention means are provided for causing the release of the detent a predetermined time after the closure of the starting switch 3 to energize the starting motor, this time interval being so regulated as to eiiect the removal of the detent from the pinion as soon as thepinion has become meshed with the engine gear. As here shown, this means comprises a circuit for actuating the relay It to open contacts Il, I8, and de-energize the electro-magnet I4, said circuit including provisions for delaying the energization of the relay l6 for a predetermined time. As shown in Fig. 1 the releasing circuit includes a magnetic switch 22 including a contact 23 connected by lead 24 to the lead I5, and a contact 25 connected by a lead 26 to a fixed contact 21. The detent I3 carries a contact 28 which is disengaged from contact 2! when the detent is released, but which engages said contact when the detent is actuated. Contact 28 is connected by a lead 29 to the electro-magnet 3| of the relay I6, which electro-magnet is groundedat 32 to complete the releasing circuit. Magnetic switch 22 comprises a coil 33 which is connected by a lead 34 to the lead I5, and by a lead 35 to a fixed contact 36. A contact 31 which is connected to the ground at 38 is arranged to complete the control circuit for the magnetic switch 22.

Means are provided energized concurrently with the actuation of the starting motor for opening and closing the control contacts 35, 31, said means including provisions for preventing effective closure of the control contacts for a predetermined time by causing them to vibrate before coming to rest in closed position. As illustrated this means comprises the mounting of the contact 3'! on a flexible reed 39, one end of which is anchored at 4! and the free end of which carries a pendulous weight or bob 42 adapted to be engaged by an arm 43 arranged to swing about a pivot 44. The arm 43 is normally maintained in the position illustrated resting against a stop pin 45 by means of a spring 46, and in this position the end of the arm engages thebob 42 to hold the contact 31 away from contact 36. A magnetic plunger- 4'! is pivotally connected to arm 43 as illustrated at 48, and means for actuating the plunger is provided in the form of a solenoid 49 connected by lead 5| to the lead l5 and grounded at 52 to complete its actuating circuit.

Means is provided for maintaining the energization of the releasing relay l6 after initial actuation thereof to open contacts ll, 18. This energization is suificient to hold the contacts I1, l8 open and thus prevent a second actuation of detent 13 as long as the starting switch 3 is held closed. This means is here shown as a resistance element 53 bridged across the leads I 5 and 28 having a conductance value such that coil 3| will hold contacts I1, I 8 open but will not be energized thereby sufliciently to open said contacts.

In the operation of this embodiment of the invention, starting with the parts in the positions as illustrated, closure of the starting switch 3 by the operator causes completion of the start ing circuit through the motor 5 which is thereupon actuated to cause rotation of the armature shaft and consequently of the screw shaft 9. Concurrently with the closure of the starting cir- Quit the detent i3 i actuated by the energization of electro-magnet l4 through lead I5, contacts ll, 18, lead [9 and ground connection 2|. The detent l3 accordingly resists the rotation of the pinion H in order to assure its traversal along the screw shaft into engagement with the engine gear. Actuation of the detent I3 also serves to close contacts 21, 28.

Clostu'e of the starting switch 3 also causes energization of the solenoid 49 through lead 6| and ground connection 52 whereby the arm 43 is drawn downward, releasing the vibrator reed 33. After a predetermined period of vibration, the contact 31 comes to rest against the contact 36, thereby causing energization of the electro-magnet 33 of the magnetic switch 22 by virtue of its a connection 34 to the lead l5 and its connection 35 to contact 36. The consequent closure of magnetic switch 22 completes the circuit for the releasing relay l6 through lead I5, 24, switch 22, lead 26, contacts 21, 28, lead 29 and ground connection 32. The energization of relay l6 thus releases the detent 13 by opening contacts I1, 18, and said contacts are thereafter maintained open by a small amount of current traversing the resistor 53 which serves as a bridge across the contacts 21, 28 when they are opened by the release of the detent.

The embodiment of the invention illustrated in Fig. 2 is substantially the same as that illustrated in Fig. 1 except that the electro-magnet 49 of the vibrator time delay instead of being actuated immediately upon closure of the starting switch 3 as illustrated in Fig. 1 is not actuated until after the detent I3 has been moved to operative position. Thi is accomplished by connecting the electro-magnet 49 to the detent contact 21 by mean of a lead 54 attached to the release circuit lead 26. For convenience, the magnet 33 of the magnetic switch 22 is also connected as illustrated to the same lead'54.

The operation of this embodiment of the invention is the same as previously described, except that the actuation of the time delay for the pinion release is dependent upon and instituted by the closure of the detent-controlled contacts 21, 28.

Although but two embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter a starting circuit including a motor, a pinion actuated by the motor to engage and rotate a member of an engine to be started, a detent for opposing rotation 01 the pinion, electro-magnetic means energized upon closure of the starting circuit for actuatinl the detent to engage the pinion, electro-magnetic means energized upon actuation of the detent ior causing release of the actuating means, and means for delaying efiective energization of the releasing means for a predetermined time.

2. In an engine starter a motor, a pinion. threaded means actuated by the motor to cause the pinion to engage and drive a member of an engine to be started, a magnetic detent for resisting rotation of the pinion so as to ensure its traversal when tne motor begins to rotate, means ior energizn'lg said detent including normally closed contacts, electro-magnetic means energized upon actuation of the detent for controlling the opening of said contacts including a pair of normally open contacts, and means, energized from the starting circuit causing closure of the normally open contacts, said last means including provisions for causing the normally open contacts to vibrate for a predetermined time before remaining closed.

3. In an engine starter a motor, a pinion, means including a threaded connection between the motor and pinion for moving the pinion into mesh with an engine member upon rotation 01 the motor, a detent for resisting rotation of the pinion in order to ensure its traversal into operative position, means for simultaneously causing actuation of the detent and o! the starting motor, means including a relay controlled by the detent for tie-energizing thedetent a predetermined time aiter the actuation thereoi, and means for maintaining the energization of the relay as long as the starting motor remains energized.

4. In an engine starter a starting circuit including a motor and a starting switch, a pinion having a threaded connection with the motor and actuated to engage and drive 'a member of an engine to be started, a detent for resisting rotation of the pinion to ensure its traversal, an electro-magnet energized by closure of the starting switch to actuate the detent, a relay for deenergizing said electro-magnet, means for actuating said relay a predetermined time after actuation of the detent, and means controlled bythe starting switch for maintaining the relay enersized.

FRANK T. CHRISTIAN. 

